Real-time monitoring system enabling high-yield co-linear fabrication of electronic-photonic integrated circuits

The simultaneous fabrication of electronic and photonic devices in a co-linear manner is crucial for the heterogeneous integration process. During this process, waveguide surfaces are susceptible to contamination by doping elements and residual metals from processing equipment, leading to a significant increase in propagation loss. Experimental results suggest that hydrogen annealing can effectively reduce the propagation loss of silicon waveguides to as low as 0.9 dB/cm. However, it should be noted that excessive high-temperature processing may negatively impact performance. Comparative analysis of different doping elements revealed that propagation loss remained relatively stable when surface concentrations of elements such as B, P, and As reached 10¹⁷ atom/cm³. In contrast, a significant increase in propagation loss was observed at the critical concentration threshold of 10¹⁸ atom/cm³ for Ge, with a further deterioration of 42% in loss following high-temperature annealing at 1150 °C. In this paper, an innovative real-time monitoring system based on inductively coupled plasma mass spectrometry is introduced, enabling precise control at critical process stages and enhancing wafer yield. Furthermore, long-term stability assessments indicated that after 24 months of ambient storage, the propagation loss increased by only 0.3 dB/cm, highlighting the excellent environmental robustness.